<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        img[src="images/apple100.jpg"] {
            width: 50px;
        }
    </style>
</head>
<body>
    <!-- 模糊的 -->
    <img src="images/apple50.jpg" alt="">
    <!-- 清晰的 -->
    <img src="images/apple100.jpg" alt="">
</body>
</html>